Syntax

Name Resolution Rules

3

Each task_name
is expected to be of any task type; they need not all be of the same
task type.

Dynamic Semantics

4

For the execution of an abort_statement,
the given task_names
are evaluated in an arbitrary order. Each
named task is then aborted, which consists of making the task
abnormal and aborting the execution of the corresponding task_body,
unless it is already completed.

5

When
the execution of a construct is aborted (including that of a task_body
or of a sequence_of_statements),
the execution of every construct included within the aborted execution
is also aborted, except for executions included within the execution
of an abort-deferred operation; the execution of an abort-deferred
operation continues to completion without being affected by the abort;
the following are the abort-deferred operations:

6

a protected action;

7

waiting for an entry call to complete
(after having initiated the attempt to cancel it — see below);

8

waiting for the termination of dependent
tasks;

9

the execution of an Initialize procedure
as the last step of the default initialization of a controlled object;

10

the execution of a Finalize procedure
as part of the finalization of a controlled object;

If the execution of
an entry call is aborted, an immediate attempt is made to cancel the
entry call (see 9.5.3). If the execution
of a construct is aborted at a time when the execution is blocked, other
than for an entry call, at a point that is outside the execution of an
abort-deferred operation, then the execution of the construct completes
immediately. For an abort due to an abort_statement,
these immediate effects occur before the execution of the abort_statement
completes. Other than for these immediate cases, the execution of a construct
that is aborted does not necessarily complete before the abort_statement
completes. However, the execution of the aborted construct completes
no later than its next abort completion point (if any) that occurs
outside of an abort-deferred operation; the following
are abort completion points for an execution:

16

the point where the execution initiates
the activation of another task;

Bounded (Run-Time) Errors

20

An attempt to execute an asynchronous_select
as part of the execution of an abort-deferred operation is a bounded
error. Similarly, an attempt to create a task that depends on a master
that is included entirely within the execution of an abort-deferred operation
is a bounded error. In both cases, Program_Error
is raised if the error is detected by the implementation; otherwise the
operations proceed as they would outside an abort-deferred operation,
except that an abort of the abortable_part
or the created task might or might not have an effect.

Erroneous Execution

21

If
an assignment operation completes prematurely due to an abort, the assignment
is said to be disrupted; the target of the assignment or its parts
can become abnormal, and certain subsequent uses of the object can be
erroneous, as explained in 13.9.1.

NOTES

22

41 An abort_statement
should be used only in situations requiring unconditional termination.